This is a study to determine the response of bone turnover in older women to the following doses of estrogen: placebo, 0.25 mg/d, 0.5 mg/d,1.0 mg/d. All women will receive calcium and vitamin D supplementation. We will also emphasize recruitment of black and Hispanic women to determine if there are differences in bone turnover, bone density and the response of bone turnover to estrogen between these ethnic/racial groups. To date, 28 white women and 1 black woman have been enrolled. Our target is 60 white women, 40 black women, and 20 Hispanic women.